Contraction joint for concrete



Feb. 27, 1945. A, FlsCHER 2,370,153

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Feb. 27, 1945. A. Q FlsCHER 2,370,153

CONTRACTION JOINTS FOR CONCRETE Filed April 9, 1941 2 SheebS-Sheet 2 fgigl. fw 12' Patented Feb. 27, 1945 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates to contraction joints embedded in concrete pavements as a means whereby cleavage of a section of pavement under internal stresses of contraction may be restricted to desirable geometrical lines and in rationally distributed vertical lplanes of subdivision, rather than along irregular linesy at random. While the need for such contraction joints is .perhaps greatest along the centerline of roadway, they are desirable also in transverse positions, paralleling but suitably spaced from expansion joints that will likewise be employed.

One object of the invention is to provide suitable constructions of thin subdivision plates which. by extending through a suitable proportion of the vertical dimensions of the paving slab or entirely through the same in certain selected planes will enable the slab under stresses of contraction developing therein, to pull apart in said planes rather than elsewhere; it being contemplated that such plates may be left permanently in position in the concrete or withdrawn therefrom and replaced by a poured filler as may be desired. Such plates may be made of thin metal; strips of resinized lignin or other preserved board; thin mastic material preferably housed between layers of felt; a strip of asbestos lumber or in fact any non-perishing material capable of maintaining inherent rigidity and strength admitting of manipulation into the position of and serving the functions of the division template for two adjacent poured concrete slabs. These plates, especially if made of sheet steel, are preferably provided with a protective coating nf rubberized bituminous material. They may be formed with any desired sectional form such as corrugated or other form that will contribute to their integrity and adapt them to better coact with means for holding them in erect position while the concrete is being poured.

Another object of this invention is to provide constructions of contraction joint plates that will enablethem to be made in two assembled sections separable along a horizontal line and both of which may be left permanently in the position nf a cleavage dening plane in the concrete, or the upper one of which may be withdrawn after the concrete has set. while the lower section is left permanently in such position; said sections being provided with means facilitating their assembly in functioning position or their separability and release of the upper section when desirable.

Another object of the invention is to provide water-stop means in association with any of the various types of contraction Joint plates herein contemplated; some of said water-stop means being adapted for association in general with a cleavage defining plate; some of them being especially designed for association with plates having separable sections, the upper one of which is removable; and others being combined with subdivisible cleavage plates in a manner to assist in the assembly of the two plate sections; to pack the joint between the sections when assembled; and to serve as a water-stop upon the lower section that remains permanently in place and prevents water from reaching the foundation of the pavement after the upper section of the cleavage plate is withdrawn.

In the accompanying drawings:

Figures 1 and 2 are elevational views of portions of the two constituent sections of a subdivisible cleavage plate constructed for assembly in a vertical plane by interconnection of their meeting horizontal margins through means of pins on the margin of one section entering sockets on the margin of the other section.

Figures 3 and 4 are respectively, a top plan view and a section on the line 4--4 of Figure 3 showing a water-stop applicable to the divisible cleavage plate shown in Figures 1 and 2.

Figure 5 is a vertical section through abutting slabs of concrete and in which are embodied the sectional cleavage plate of Figures 1 and 2 and the water-stop of Figures 3 and 4.

Figures 6 and '7 are respectively an elevational view and a section on the iline 1--1 of Figure 6, showing a. portion of a non-divisible cleavage plate together with a portion of one of two wings of a water-stop secured in position on opposite sides of a cleavage plate, by vulcanization or other form of interadhesion, reenforced by eX- tension of portions of the wings through perforations in the plate and their union by vulcanization thereat.

Figures 8 and 9 are respectively an elevational view similar to Figure 6 and a section on the line 9-9, Figure 8, showing the cleavage plate crete sections and which may be desirably used in anchoring contraction joint plates as well.A

Figures 10 and 11 are, respectively, an eleva- Y tional view similar to Figure 8 and a section on the line Il-H of Figure 10, illustrating the use of an angular lateral deection in the cleavage plate, that gives form to a tongue-and-groove lioint between the two slabs of concrete as a limitation of vertical relative movement between the said slabs in case of impairment of their fo'undations; andI incidentally using the apex of said deflection as the locus oi anchoring pins if and when said pins are employed.

Figures 12 and 13 are respectively an elevational view and a section on the line Iii-I3 of Figure 12 illustrating the use of a plurality of vertically spaced water-stops of the same general type as that employed in Figures 6 to 11 inelusive.

Figure 14 is an elevational view of a portion of a divisible cleavage plate for contraction joints together with a portion of a water-stop that packs the connection between the plate sections and helps to hold said sections releasably in assembly; and Figure 15 is a sectional view of two slabs of concrete having their plane of cleavage defined by the plate of Figure 14, and packed by the water-stop thereof; the plane of section of said plate and water-stop being indicated by the line I5-I5 of Figure 14.

Referring to Figures 1 to 5 inclusive, I and 2 represent upper and lower sections of a two part cleavage plate for contraction joints. These sections are separably united edgewise to each other by suitable means which enables the sections as a unit, to be manipulated into position to have concrete cast about whereby the concrete will be caused to form according to the relation of the vertical dimension of the plate to the thickness of the concrete either two separated slabs, or one slab so nearly separated that when internal stresses of tension develop in the concrete it will be drawn asunder in a plane or planes defined by the plate. The means for separably uniting the plate sections, shown by way of illustration, in Figures l to 5, comprises pins 3 on one section which may be set thereinto, for instance the upper section interengaging with sockets 4, receiving said pins, on the other or lower section; and this means of interengagement is preferably reenforced by a body 5, 6, of plastic material having openings I in which it receives sockets 4, thereby enveloping the pins and sockets. Said body of plastic material preferably comprises two undercut wings 5, 6, in positions to be embedded in the concrete and having pliability or resiliency that enables them to yield to tension and compression of the concrete slabs without losing Water tight relation to the concrete. Hence the parts I, 2, 5 and 6 together constitute a waterstop cleavage plate for contraction joints.

According to Figures 6 and 7 the cleavage plate 8 may be made as a single sheet and water-stop wings 9, I0, Figures 6 and '7 may be vulcanized to opposite faces thereof and their interattachment may be reenforced by having portions of the wings restricted in section, project into openings II and vulcanized or otherwise adhered together Where they meet.

According to Figures 8 and 9, wings 9a, Illa on plates 8a may be associated on the same plate, with anchor pins I3 set in perforations I2, thus relieving the wings of destructive shear that might result from relative vertical movement between the slabs of concrete.

In Figures 10 and 11 the cleavage plate 8b is laterally deflected, angularly as suggested at I4 in order to mold the two slabs of concrete with a tongue-and-groove assembly which has the effect of limiting 'vertical relative movement between the slabs. This control over the slabs is in addition to that afforded by pins Ila in holes I 2b located along the apex of the angular deflection.

As illustrated in Figures 12 and 13, a pair of wings 8d, lod, vulcanized to the plate and united together through holes I I d to form a second water-stop, effective for preventing water from rising up from below, may be employed in addition to the first water-stop 8c. IlIc united through holes Iic and arresting water entering from above, employed, thus exemplifying the principle of a multiple water-stop cleavage plate.

Figures 14 and 15 illustrate a modified design of water-stop cleavage plate made of a plurality of releasably assembled sections. Here the lower plate section 8f is formed with a groove Il, It, having a justifying step I1 at the bottom, and the upper section 8e has its meeting edge formed as a tongue I6 entering said groove, and snugly fit ting in said step Il independently of the waterstop, while water-stop material Sc, IUc. is so introduced between the walls I5, I5 of the groove and the tongue I6 above the step Il, as to pack the connection against lost motion and seal it against seepage of water.

Whether the water-stop wings be of T-shaped section as shown in Figures 1 to 5, or dove-tail shape as shown in Figures 7, 9, 11, 13 and l5, they constitute eiective water-stops since their outwardly enlarging sections in the matrices that form about them in the concrete cause them to press water tight against the contines of the matrices, under contraction of the concrete and to resume positions in which they illl such matrices when the concrete expands again. This principle of water-stop foxconcrete pavements is described and claimed ln previous applications filed by the present inventor, for instance application Serial No. 243,004, led November 29 1938; No. 379,671, filed February 19, 1941 and No 381,971, filed February 19. 1941.

I claim:

1. A plate-like subdivider for contraction joints formed of two sections separably united by male and female portions and one of said sections carf ries a body of plastic material against which both sections abut and which waterproofs the connection between the sections.

2. In a contraction joint for concrete sections asubdividing plate comprising two sections constructed respectively with a reentrant jointing portion and a projecting jointing portion removably entering said reentrant portion and holding said sections in alinement; one of said sections also having a body of plastic material embracing said jointing portions and reducing relative movement between the jointing portions while they are in assembly.

3. A contraction joint as described in claim 2 in which the body of plastic material has waterstop extensions embedded in the concrete on either side of the subdividing plate.

4. In a contraction joint for concrete, comprising a thin subdividing plate formed of two detachably superposed sections and plastic waterstop in water arresting connection with said plate and having an extension embedded in and having water sealing relation to the concrete at one side of the plate.

5. A contraction joint for concrete bodies comprising a thin subdividing plate formed of two detachably superposed sections and a plastic water-stop body in water tight relation to said plate said plastic body having extensions on opposite sides of said plate, embedded in water-stop relation to said concrete.

6. A contraction joint as described in claim 5 when the plastic body is adhered to the plate.

7. A contraction joint as described in claim 4 in which the lower section of the subdividing plate is xed and carries the water-stop while the 5 upper section is removable independently of the water-stop.

8. In a contraction joint for concrete pavements, a. subdividing plate comprising a lower section constructed with a jointing groove and an 10 upper section constructed with a tongue enter- 

